Such a connecting rod, shown in FIG. 1 with the reference 1, has a generally tubular hollow main body 2 extending along a general direction AX and extended at each of its ends by respective two-lug clevises, these clevises being given references 3 and 4.
In a method known from patent document FR 2 893 532, the connecting rod is fabricated using a piece of reinforcing fiber fabric that is cut to have a shape as shown in FIG. 2. This shape comprises a central portion for the hollow main body 2 and four extensions, each corresponding to a respective one of the clevis lugs.
The fabric used is a three-dimensional woven fabric of carbon fibers, i.e. a fabric of relatively large thickness made up of reinforcing fibers that are woven together in three dimensions. By way of example, such a three-dimensional fabric corresponds to a 2.5 D type fabric.
Such a fabric has a plurality of layers of longitudinal fibers, and a plurality of layers of transverse fibers that are woven together in such a manner that the fibers extending in one direction are interlinked with the fibers in a plurality of other layers in order to constitute a non-separable fabric.
The fabric may optionally be reinforced in the clevises: some of the fibers of the various layers are then no longer interlinked in the clevises so as to leave layers that are not mutually interlinked. This makes it possible to insert additional layers in the clevises in order to increase their thickness.
Additional fibers extending substantially perpendicularly to the plane of the layers may subsequently be stitched through the various layers making up the clevises in order to secure them to one another.
Fabricating such a clevis consists in folding the piece of fabric shown in FIG. 2, which piece of fabric is optionally reinforced in its clevises, by applying it onto a mandrel or the like and then bringing together its two opposite edges. The edges can then be connected together, e.g. by stitching, prior to injecting resin into the reinforcing fiber fabric and heating the assembly in order to polymerize the resin.
The nominal thickness of the wall forming the connecting rod is limited by the thickness of the three-dimensional fabric that is used for making it, given that deciding to use a thick fabric increases the cost of such a fabric very considerably, in particular because it involves reducing the speed of weaving very considerably.
In practice, given current sales costs, it is not possible to envisage using a fabric having a thickness of more than two or three centimeters. It can be understood that such a limitation on thickness puts a limitation on the forces that can be accepted by the connecting rod in question as a whole, and also by its clevises.